Doesn't matter? There are still lots of places that try to filter user submitted html and javascript to "sanitize" it. And a lot of those filters are blacklist

Doesn't matter? There are still lots of places that try to filter user submitted html and javascript to "sanitize" it. And a lot of those filters are blacklist based rather than whitelist. But here we have an example of how it's possible to create any javascript program with purely non alpha-numeric input. I can guarantee you that such a result is immediately applicable to a lot of places around the web. It constitutes an attack vector making it possible to execute arbitrary javascript code in areas where that is allegedly blocked. Exactly how much of an impact that vector has is currently unknown, and hopefully not very large because many devs have realized the futility of trying to filter such things. However, if there were a magic wand that you could wave which would show the maximum impact of a particular vulnerability and identify all of the sites in the world which were vulnerable and notified all of the site owners instantly with a full report I can guarantee you that there would be a lot of people out there with some sleepless nights and a lot of emergency work ahead of them.